Advanced thermal personal protection articles which use insulation batting materials will have to meet demands for an acceptable environment. Flammability, smoke toxicity, mold and mildew formation, loss of insulation performance when wet, dust and other irritants are only a short list of the problems found with the current materials used as insulation for personal articles such as garments and sleeping bags.
The prior art has used fowl down and feathers, asbestos, wool, polyester and polypropylene fibers and various foam materials such as polyurethane foam as thermal insulation for many applications. Fowl down is the most desired light weight thermal insulation material. Current thermal protection materials most commonly used as substitutes for down are thermoplastic fibrous materials which provide fair to adequate thermal insulation at some additional weight, but are less than acceptable because they are flammable, melt when subjected to modest amounts of heat and can generate toxic fumes when burned. In addition, such prior art materials absorb moisture and water and none have the capabilities of forming buoyant light weight structures even when coated with water-repellant materials as provided by the present invention.
There is a further need for buoyant light weight non-wettable insulation in aircraft which is effective for thermal changes and for sound absorbency. Current use of coated fiberglass results in additional weight for the aircraft and does little to help to maintain buoyancy of small aircraft in water.
U.S. Pat. No. 4,167,604 to William E. Aldrich discloses the use of crimped hollow polyester filaments in a blend with down in the form of a multiple ply carded web which is treated with a thermosetting resin to form a bat having thermal insulating characteristics. The web, however, does not have any buoyancy and has moisture retention properties.
U.S. Pat. No. 4,321,154 to Francois Ledru relates to high temperature thermal insulation material comprising insulating mineral fibers and pyrolytic carbon. To make the insulation light weight, an expanding agent is utilized or hollow particles such as microspheres are utilized. Although light weight, this material is not buoyant and absorbs moisture.
U.S. patent application Ser. No. 108,255 filed Oct. 13, 1987, entitled "Sound and Thermal Insulation" of McCullough, et al, which is herewith incorporated by reference, discloses non-linear, carbonaceous fibers and fibrous structures which can be utilized in the present invention.
U.S. Pat. No. 4,371,585 to Memon, which is herewith incorporated by reference discloses a process for applying a silicone or siloxane coating which may be utilized in the present invention.
The brochure of the Dow Corning Corporation entitled "Dow Corning Materials For High Technology Applications, 1986", which is herewith incorporated by reference, discloses silicone products including silicone elastomers, organofunctional silanes, chlorosilanes, etc. which can be used as coating material in preparing the buoyant structures of the invention.